Question: Balance the following chemical equation: $ $ $\text{Mg(OH)}_2 +$ $\text{HCl} \rightarrow$ $\text{MgCl}_2 +$ $\text{H}_2\text{O}$
Solution: There is $1 \text{ Mg}$ on the right and $1$ on the left, so $\text{Mg}$ is already balanced. There are $2 \text{ Cl}$ on the right and only $1$ on the left, so multiply $\text{HCl}$ by ${2}$ $ \text{Mg(OH)}_2 + {2}\text{HCl} \rightarrow \text{MgCl}_2 + \text{H}_2\text{O} $ Now there are $4 \text{ H}$ on the left and only $2$ on the right, so multiply $\text{H}_2\text{O}$ by ${2}$ $ \text{Mg(OH)}_2 + 2\text{HCl} \rightarrow \text{MgCl}_2 + {2}\text{H}_2\text{O} $ Now $\text{O}$ is balanced too. The balanced equation is: $ \text{Mg(OH)}_2 + 2\text{HCl} \rightarrow \text{MgCl}_2 + 2\text{H}_2\text{O} $